PERMANENT OPERATING CONDITIONS Ad reserved for radio-equipped avions. Radio contact mandatory. Radio contact mandatory before entering the RMZ. Ban specific to AD HEL: school flights and training flights are prohibited AD usage restrictions ULM of classes 1, 2, 4, 5 and 6 prohibited. Aerobatics: Activity reserved for avions and pilots authorized by French Aviation Authority DSAC Nord and according to protocol. piste 10: reduced Distance de décollage disponible, presence of a road pattern at 14 m from runway end.